The invention lies in the field of medical technology and concerns a method, a composition, and a set according for the affixing or fastening of an artificial element to a surface of dentine, tooth enamel, bone tissue, or of a corresponding substitute material.
It is well known in dentistry to make e.g. fillings, inlays, dental veneers, or cement for fixing brackets of dental braces, crowns, inlays or bridges from composite materials. These composite materials usually comprise a curable matrix material and filler materials contained in the matrix material. The composite materials are applied in the form of a paste to the surface where they are to adhere and they are cured in situ. The matrix material is e.g. a polymer which is curable by cross-linking, it is e.g. based on polymethacrylate or polymethylmethacrylate, wherein the in-situ curing is initiated by ultraviolet light. The filler material is e.g. a ceramic material, a glass-ceramic, or a glass, and is contained in the matrix material as e.g. particles, fibers, or whiskers.
In order to achieve an effective bond between the aforementioned composite materials and the dentine or enamel surfaces of the tooth, these surfaces are pre-treated. For this preparatory treatment e.g. etching agents, sealing agents, adhesion promoters and/or adhesion agents are used, which are either applied in succession (e.g. adhesive systems of conditioner, primer, and adhesive) or which are contained within a single primer preparation requiring just one application. One of the purposes of the preparatory treatment is to render the inherently hydrophilic dentine and enamel surfaces receptive to the usually hydrophobic composite material to be adhered to it, to create covalent or ionic bonds with molecules of the dentine or enamel surface, and to provide molecules capable of covalent or ionic bonding between the pre-treated surface and the material to be attached to it. Corresponding molecules and preparations belong to the state-of-the-art technology.
Usually at least one of the pre-treatment preparations comprises a polymer which is curable by cross-linking and/or corresponding monomers or oligomers, wherein this polymer is adapted to the matrix material of the composite material to be affixed to the pretreated surface in such a way that cross-linking between components of the pre-treatment preparation and the matrix material becomes possible.
The aforementioned pre-treatment preparations are usually applied to the dentine or enamel surface in one or several steps of preparatory treatment and, if necessary, partly cured. Then the composite material is applied to the pre-treated dentine or enamel surface and the composite material is cured, wherein not fully cured components of the pre-treatment preparation are completely cured also.
It is also a known practice to affix implants to bones or bone sections, wherein a bone cement is applied between the implant and the bone or bone section. Such cements are also solidifiable (curable) and fulfill similar functions as the aforementioned pre-treatment preparation used in dentistry. The cements can be polymer, ceramic or hydraulic cements and usually also contain filler materials.
Another procedure known e.g. from the publications WO 02/069 817, WO 2004/017 857, and WO 2005/079 696, is to fasten elements, consisting at least in part of thermoplastic material, to surfaces of bone tissue, dentine, or tooth enamel, by pressing the element against said surfaces and exciting it with mechanical vibration, e.g. ultrasonic vibration, so that the thermoplastic material is softened at the contact surfaces and pressed into pores and surface irregularities of the bone tissue, dentine, or enamel, in order to form a form-fit connection after re-solidification. This method has the important advantages that there is no need for a preparatory treatment of the surfaces and that, compared to the method using curable composite materials as briefly mentioned above, causes less or practically no shrinkage.